module ctr_comb (CurState, NextState);

    input           [2:0]   CurState;
    output  reg     [2:0]   NextState;

    always @    *
        case ({CurState})
            3'b000:  NextState = 3'b001; 
            3'b001:  NextState = 3'b010;
            3'b010:  NextState = 3'b011;
            3'b011:  NextState = 3'b100;
            3'b100:  NextState = 3'b101;
            3'b101:  NextState = 3'b101;
            default: NextState = 3'b000;
        endcase

endmodule
